Hi everyone

Firstly I would just like to say what a great forum you have going here for the RX8 and how informative it has been in helping me decide between a 350Z and the RX8.
Anyway now I'm hooked on the RX8 and am about to place an order for a UK car, but first I have some questions.
I'm considering the optional sports exhaust (£450), what difference, if any, does this make to the sound/performance/appearance?
I'm also interested in the polished alloys but at £375 per wheel the're pretty pricy.
If these extras are ordered with the car, should I expect Mazda UK, or the dealer to give me an allowance for the standard parts? So far there has been no mention of this and it would appear that Mazda get to keep the standard parts and they are not passed on to the new owner, so in effect you end up paying for something twice, sounds a bit of a rip-off to me.
What do you guys think?
Basically I just want to know if the exhaust is worth buying and whether I should expect somekind of a deal on it along with the alloys.